How do you adjust a base on an infant safety 1st car seat?

On the base that goes with my daughters car seat there is a handle that says pull to adjust base. I pulled it but it just went back in. Do I need to have the car seat in the base for it to work or what do I do? I'm not sure where the owners manual is.|||What do you mean adjust the base?... My carseat base has nothing to adjust... you just strap it in with the seatbelt and you're good to go.|||try using the seat without the base. since safety is most important, follow up with the pros at the local fire department or ambulance service for guidance with installation.